LESS COMMON, NOT LESS IMPORTANT: A SPOTLIGHT ON ATYPICAL DIABETES

Medically Reviewed by Dr. Sony Sherpa (MBBS) - October 11, 2023

Diabetes is a common metabolic disorder that impairs the body's capacity to turn food and drink into energy. According to the World Health Organization (WHO), around 422 million people worldwide have diabetes, and diabetes is directly responsible for 1.5 million deaths annually.

We know the two most common types, Type 1 and 2. When the insulin producing cells in the pancreas are destroyed by the body, it leads to development of Type 1 diabetes, an autoimmune disease. When the body produces insulin but can no longer effectively utilize it, Type 2 diabetes develops.

Occasionally, patients may have other forms of diabetes that do not fit the traditional pattern of either Type 1 or Type 2 diabetes and can be labeled 'Atypical diabetes'. Atypical diabetes is a less common kind of diabetes in which patients have symptoms and health conditions that differ from the two most common types of diabetes. Mitochondrial and ketosis-prone diabetes, Monogenic diabetes, and Latent Autoimmune Diabetes in Adults are all examples of Atypical diabetes.

Atypical diabetes frequently has a known genetic basis, yet people often go untreated, and the condition goes undiscovered since the tests are rarely done. It is critical to identify patients with atypical diabetes since treatment and prognosis differ from those of Type 1 and Type 2 diabetes. Furthermore, people with atypical diabetes are frequently misdiagnosed as having Type 1 or 2 diabetes, leading to unnecessary insulin administration and screening for complications.

Atypical Forms of Diabetes

Among the various types of diabetes, the most prevalent are Type 1 diabetes, Type 2 diabetes, Pre-diabetes, which is when blood glucose levels exceed the normal range but not enough to be officially identified as Type 2 diabetes, and Gestational diabetes, which can manifest in some pregnant women. 

Although Type 1 or Type 2 diabetes is the most common diagnosis for adults and children with diabetes, many people may not fit the diagnostic criteria for either type or exhibit unusual symptoms of their condition.

Monogenic Diabetes

Monogenic diabetes is diabetes caused by a single gene mutation. If a parent carries this genetic mutation, their children have a 50% chance of inheriting it.

The pancreatic beta cells malfunction as a consequence of the genetic mutation. As a result, the body is unable to produce enough insulin. Insulin resistance can develop in some people.

Over 20 distinct gene mutations have been discovered as the root causes of various kinds of monogenic diabetic syndromes. These are further classified into two types:

Neonatal Diabetes Mellitus (NDM)

This occurs in neonates and infants. It usually manifests itself within the first six months of life. Around 20% of patients with neonatal diabetes experience developmental delays (e.g., muscle weakness, learning issues) and seizures.

NDM, unlike Type 1 diabetes, is not an autoimmune disorder (in which the body destroys insulin-producing cells). A mutation in a gene that influences insulin synthesis causes neonatal diabetes. This means that blood glucose levels in the body skyrocket.

There are two kinds of neonatal diabetes: Permanent and transient.

Transient neonatal diabetes, as the name implies, usually disappears by the age of 12 months. However, it commonly returns later in life, mainly during adolescence. It is responsible for 50-60% of all cases. As you may guess, permanent neonatal diabetes lasts a lifetime and accounts for 40-50% of all cases.

Maturity-Onset Diabetes of the Young (MODY)

MODY is an uncommon form of diabetes that differs from both Type 1 and Type 2 diabetes and runs in families. Most cases of monogenic diabetes are autosomal dominant, which implies that a child can inherit the illness from either parent.

If a child inherits the mutation, they will most likely acquire MODY before age 25, regardless of weight, lifestyle, ethnicity, or other factors. Some children with monogenic diabetes, on the other hand, have new (de novo) mutations that do not come from either parent.

Because MODY is so uncommon, clinicians may be unaware of it, and it is estimated that 90% of people suffering from MODY are initially misdiagnosed with Type 1 or Type 2 diabetes.

The following are the most prevalent forms of MODY:

• HNF1-alpha

This gene is responsible for around 70% of MODY cases. In this case, a decrease in the amount of insulin the pancreas produces is what leads to diabetes. Diabetes typically develops in childhood or early adolescence, and people with HNF1-alpha MODY do not require insulin as they can be managed with small quantities of a class of drugs known as sulphonylureas (commonly used in type 2 diabetes).

• HNF4-alpha

This is less prevalent than the other types of MODY. People who have inherited a variation in this gene are more likely to have weighed 9lb or more (about 4kg) at birth. They could have had low blood glucose at or shortly after birth, necessitating treatment. People with HNF4-alpha are usually treated with a sulfonylurea drug. However, they may eventually require insulin.

• HNF1-beta

This type of MODY can cause various issues, including renal cysts (kidney cysts), uterine abnormalities, gout, and diabetes. Renal cysts are frequently identified in the womb before a baby is delivered. Diabetes typically develops later in life when insulin medication, a healthy balanced diet, and frequent physical activity are usually required. There is also an increased risk of complications of diabetes associated with HNF4-beta MODY.

• Glucokinase

This gene aids the body in determining how high the blood glucose level is. When this gene fails to function correctly, the body allows blood glucose levels to rise above normal. Blood glucose levels in glucokinase MODY patients are frequently slightly higher than normal, ranging between 5.5-8 mmol/l. Because you do not usually experience symptoms of this type of MODY, it is commonly detected through routine testing (for example, during pregnancy). There is no need for treatment for glucokinase MODY.

Wolfram Syndrome

Wolfram Syndrome, commonly known as DIDMOAD syndrome (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy, and Deafness), is a rare genetic disorder. Symptoms of Wolfram syndrome type 1 can differ from person to person. However, they frequently appear in a predictable order during childhood and adolescence.

The following is the typical sequence and age at which symptoms appear:

• Diabetes Mellitus (age 6): Diabetes mellitus differs from Type 1 diabetes because it is not an autoimmune illness. You also have a lower risk of microvascular complications such as nephropathy (which can lead to kidney failure) or retinopathy (which can lead to blindness). However, it is treated like Type 1 diabetes with insulin injections, blood tests, a well-balanced diet, and regular physical activity.
• Optic Atrophy (age 11): Optic atrophy is a breakdown of the optic nerve, which transmits signals from the eyes to the brain. Blurred, dimmed, or impaired peripheral (side) vision are symptoms.
• Sensorineural hearing loss (age 13): Sensorineural hearing loss occurs due to inner ear damage. This form of hearing loss frequently worsens with age and can lead to deafness.
• Diabetes Insipidus (at age 14): Diabetes insipidus is unrelated to type 2 diabetes. It is related to the synthesis of an antidiuretic hormone, which regulates the amount of water in your urine. People with diabetes insipidus produce excess amounts of watery urine. Excessive urine can lead to dehydration, electrolyte imbalances, dry mouth, weakness, and constipation.

Alström Syndrome

Alström syndrome is an uncommon disorder that affects several body systems. Many of the signs and symptoms of this disorder arise in early childhood or infancy, whereas some appear later in life.

Alström syndrome is distinguished by progressive blindness and deafness, dilated cardiomyopathy (heart disease that enlarges and weakens the heart muscle), Type 2 diabetes, obesity, and a short height. This condition can lead to severe or fatal medical issues with the kidneys, bladder, liver, and lungs.

Latent Autoimmune Diabetes In Adults (LADA)

A type of diabetes that develops in adulthood and gradually gets worse over time is called Latent Autoimmune Diabetes in Adults (LADA). LADA, like Type 1 diabetes, occurs when the pancreas stops producing insulin. This is mainly due to an autoimmune mechanism causing pancreatic cell damage. However, unlike Type 1 diabetes, the progression in LADA is gradual. As a result, people with LADA frequently do not require insulin immediately.

Many studies believe LADA is a Type 1 diabetes that manifests much more slowly in adults. It is also known as Type 1.5 diabetes. However, some wonder whether LADA should be classed differently in this manner. Instead, they consider this as the same disease, Type 1 diabetes, that manifests differently in adults than in children.

Steroid-Induced Diabetes

Steroids can cause high blood glucose (sugar) levels. That is why some people who use steroids develop diabetes. This phenomenon is known as steroid-induced diabetes and is more likely to occur in individuals predisposed to Type 2 diabetes.

Cystic Fibrosis Related Diabetes

Cystic fibrosis diabetes is the most frequent form of diabetes in people with Cystic Fibrosis. Cystic Fibrosis creates sticky and thick mucus, which can accumulate in the pancreas, lungs, and other organs.

People with cystic fibrosis may develop Type 1 or Type 2 diabetes. Cystic Fibrosis diabetes is a distinct condition. It is the most frequent type of diabetes among Cystic Fibrosis patients. It exhibits characteristics of Types 1 and 2, but its development and treatment is different.

Newly Emerging Forms of Diabetes

Type 3c diabetes is not a new diagnosis, but the terminology is relatively unknown outside the scientific community. Type 3c diabetes is also known as pancreatogenic or pancreatogenous diabetes mellitus.

Type 3c diabetes is a form of diabetes that occurs when other diseases damage the pancreas. Pancreatic Cancer, Pancreatitis, Cystic Fibrosis, and Hemochromatosis are among the disorders associated with type 3c. Type 3c can also occur if you have had part or all of your pancreas removed due to other causes.

According to researchers, Type 3c diabetes accounts for 1% to 9% of all diabetes cases. This range is broad since Type 3c is less common, and people with the condition are frequently mistaken as having Type 2 diabetes. More research is required in this area.

Conclusion

Symptoms of atypical diabetes differ from Type 1 and Type 2 diabetes, and they can cause various health problems. Because atypical diabetes is uncommon, people are frequently misdiagnosed. They may also require different therapeutic approaches for appropriate diabetes management.

While the outward symptoms of some atypical diabetes, such as monogenic diabetes, are similar to those of more common types of diabetes, treatment differs. Some types of monogenic diabetes require insulin to control blood sugar levels. However, people with other types of monogenic diabetes benefit from various treatments, including oral medicines.

Some people can manage their symptoms with food and exercise alone, without medication. Still, others may need therapy for underlying health issues such as kidney cysts, digestive enzyme deficiencies, autism, or low magnesium levels. That is why it is critical to understand and appropriately diagnose unusual kinds of diabetes. Diabetes awareness and additional research in the field are also required.

To search for the best Endocrinology Healthcare Providers in Germany, India, Malaysia, Spain, Thailand, the UAE, UK, the USA, please use the Mya Care search engine.

To search for the best healthcare providers worldwide, please use the Mya Care search engine.

References:

• WHO: “Diabetes.” www.who.int, 13 May 2019, www.who.int/health-topics/diabetes
• Feingold KR. Atypical Forms of Diabetes. [Updated 2022 Feb 24]. In: Feingold KR, Anawalt B, Blackman MR, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279128/ 
• Kumar, Vinay, et al. Robbins and Cotran Pathologic Basis of Disease. Elsevier, 2020.
• Patil, Shivajirao Prakash. “Atypical Diabetes and Management Considerations.” Primary care vol. 49,2 (2022): 225-237. doi:10.1016/j.pop.2021.11.003
• https://www.frontiersin.org/articles/10.3389/fped.2020.540718/full
• https://www.ncbi.nlm.nih.gov/books/NBK532900/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4705145/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3137007/
• https://www.diabetes.org.uk/diabetes-the-basics/other-types-of-diabetes/latent-autoimmune-diabetes
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4112077/
• https://journals.lww.com/jaapa/fulltext/2022/11000/type_3c__understanding_pancreatogenic_diabetes.4.aspx

Disclaimer